This Phase I SBIR will develop ICPCheck, the first long term implantable, non-invasively readable intracranial pressure (ICP) monitor for hydrocephalus patients. This device will result in improved clinical management of hydrocephalus by providing a rapid and non-invasive method for detecting elevated ICP due to CSF shunt obstruction in symptomatic patients, and for monitoring and researching shunt function in asymptomatic patients. Hydrocephalus, a common condition in which CSF accumulates in the brain ventricles, is corrected by placing a VP shunt that drains excess CSF to the abdomen, maintaining ICP within normal levels. Shunts frequently malfunction, usually by obstruction, leading to a life-threatening elevation of intraventricular ICP. But the symptoms of shunt failure are unspecific - headache, nausea. Diagnosis of shunt malfunction is expensive and presents risks (exposure to radiation from CT scans, risk of infection from shunt taps and radionuclide testing) and regular, ongoing clinical management of shunted patients is complex (due to a lack of tools for investigating CSF over-drainage and for assessing the performance of specific shunt valves and siphon control devices). There are currently no non-invasive, non-radiologic technologies for detecting elevated intraventricular ICP caused by shunt malfunction. A long-term implantable intraventricular ICP monitor which can be placed during shunt surgery and which can be interrogated non-invasively thereafter would address this need - identifying malfunction where CT scan cannot (slit ventricles) and, in conjunction with the neurosurgeon's judgment, potentially ruling out malfunction and avoiding an unnecessary CT scan. The goal of this Phase I project is to develop a prototype device and to validate it in a bench model of ICP. The program will be a collaboration between NeuroDx Development (developer of ShuntCheck) and Millar Instruments (the premier cardiac and neurosurgical pressure transducer manufacturer) and is based upon two breakthrough innovations - a technology for long term drift control developed by Millar and a technology for recalibration developed by NeuroDx. Our Phase II goal will be to convert our proof-of-concept prototype into a MEMS device and to conduct full scale preclinical and clinical studies to assess the diagnostic accuracy and utility o the device in identifying elevated ICP due to shunt malfunction in hydrocephalus patients. The need for new diagnostic tools for managing hydrocephalus patients is highlighted by the NIH announcement Advanced Tools and Technologies for Cerebrospinal Fluid Shunts (PA-09-206), to which this application is responding. Our application directly responds to the request for Diagnostic tools for use in a hospital or outpatient setting that work in real-time to quantitativey determine shunt function.